1. Field of the Invention
This invention relates to a calibration device and a calibration method used to calibrate a camera mounted on a vehicle.
2. Description of the Related Art
Recent years have witnessed an increase in the use of cameras and sensors attached to vehicles for the purpose of capturing images of the vehicle periphery. When a peripheral obstruction or the like is detected by a camera or a sensor, a controller that controls the vehicle can apply an emergency brake to the vehicle while the vehicle is in motion.
The controller is also capable of synthesizing a plurality of images of the vehicle periphery, obtained via the cameras and sensors, and providing a user with the resulting synthesized image. At this time, positional and attitude relationships between the camera or sensor and the vehicle must be measured accurately to ensure that the peripheral obstruction is detected accurately or that a smooth synthesized image of the vehicle periphery is obtained.
A method of performing the measurements described above is known as a calibration method. This calibration method is essential when attaching cameras and sensors to a vehicle.
When the position and attitude of a camera or a sensor for use in a vehicle are actually calibrated, first, the controller obtains a marker disposed on the ground or a wall using the sensor. The controller then determines a position and an attitude in which the sensor is to be disposed relative to the vehicle from relative positions of the sensor and the marker and relative positions of the marker and the vehicle (see Japanese Patent Application Publication No. 2013-89984, for example).